The present invention relates to loudspeaker rigging systems and more particularly to rigging hardware for suspending a stacked array of loudspeakers of a sound reinforcement system at a predetermined location relative to an audience. The present invention has particular application in rigging a stacked array of loudspeakers wherein a vertical display between loudspeakers is desired to achieve a desired coverage and acoustic performance.
Sound systems for large venues typically involve the suspension or “flying” of stacks of loudspeakers in vertical arrays to achieve a desired acoustic output and coverage for a large audience. Such vertical stacks of loudspeakers are typically suspended and held together by rigging systems which can be attached to rigging hoists which position the stack at a desired elevation and location, typically above or in the vicinity of a performance stage. A flown stack of loudspeakers can include many speaker boxes and the rigging system for flying the stack must be strong enough to support the enormous weight of the large stack. Such rigging systems generally involve the use of metal frame elements secured to the speaker boxes that can be used to link the speakers together in a stacked arrangement and to lift the stack to an overhead flying position.
Typically, the individual speaker boxes of a vertical stack of loudspeakers held by a rigging system will have to be adjusted to meet the requirements of a particular application. Setting the proper angle between speakers, or “splay angle,” can be critical to achieving desired acoustic performance and minimizing interference between the acoustic output between speakers in the stack. Splay angles are adjusted by adjusting the linkages between the rigging frames of the stacked speakers to create a desired angle. One such adjustment method is disclosed in U.S. Pat. No. 6,640,924 issued Nov. 4, 2003 to Ian Messner (the “Messner patent”). The Messner patent discloses a rigging system wherein the splay angle is adjusted by a cam plate that pivotally extends down from the bottom front end of the side frame of one loudspeaker to engage the top front end of the side frame of the loudspeaker directly below. To set the splay angle, the cam plate must be manipulated into a cam plate receiving channel in the top of the underneath side frame and pinned when the desired cam hole is aligned with the pin hole in the under frame. This process turns out to be relatively difficult and leads to misses in the hole alignment while assembling the array. The number of pinning locations is also relatively limited.
There is a need for a rigging system for loudspeakers having splay angle adjustment capabilities that is relatively easy to assemble, and that provides a greater range and smaller increments of adjustment in the settings for the loudspeaker splay angles.